US4536213A - Reforming of higher hydrocarbons for metal oxide reduction - Google Patents

Reforming of higher hydrocarbons for metal oxide reduction Download PDF

Info

Publication number
US4536213A
US4536213A US06/648,564 US64856484A US4536213A US 4536213 A US4536213 A US 4536213A US 64856484 A US64856484 A US 64856484A US 4536213 A US4536213 A US 4536213A
Authority
US
United States
Prior art keywords
gas
furnace
higher hydrocarbons
reducing
shaft furnace
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US06/648,564
Other languages
English (en)
Inventor
Charles W. Sanzenbacher
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Mildrex International BV
Midrex International BV
Original Assignee
Mildrex International BV
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Mildrex International BV filed Critical Mildrex International BV
Assigned to MIDREX INTERNATIONAL BV A CORP. OF THE NETHERLANDS reassignment MIDREX INTERNATIONAL BV A CORP. OF THE NETHERLANDS ASSIGNMENT OF ASSIGNORS INTEREST. Assignors: SANZENBACHER, CHARLES W.
Priority to US06/648,564 priority Critical patent/US4536213A/en
Priority to CA000483992A priority patent/CA1236982A/en
Priority to AU45302/85A priority patent/AU4530285A/en
Priority to AT0234085A priority patent/AT390081B/de
Priority to ZA856109A priority patent/ZA856109B/xx
Priority to DE19853529226 priority patent/DE3529226A1/de
Priority to IN595/CAL/85A priority patent/IN164016B/en
Priority to GB08520684A priority patent/GB2164355B/en
Priority to CN 85106482 priority patent/CN85106482A/zh
Publication of US4536213A publication Critical patent/US4536213A/en
Application granted granted Critical
Priority to BR8504028A priority patent/BR8504028A/pt
Priority to FR8512706A priority patent/FR2570082A1/fr
Priority to IT22044/85A priority patent/IT1187734B/it
Priority to SE8504177A priority patent/SE8504177L/
Priority to JP60198694A priority patent/JPS6173805A/ja
Assigned to NATIONSBANK, N.A., AS AGENT reassignment NATIONSBANK, N.A., AS AGENT SECURITY INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: AMERICAN IRON REDUCTION, L.L.C.
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Images

Classifications

    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21B—MANUFACTURE OF IRON OR STEEL
    • C21B13/00—Making spongy iron or liquid steel, by direct processes
    • C21B13/0073—Selection or treatment of the reducing gases
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21B—MANUFACTURE OF IRON OR STEEL
    • C21B13/00—Making spongy iron or liquid steel, by direct processes
    • C21B13/02—Making spongy iron or liquid steel, by direct processes in shaft furnaces
    • C21B13/029—Introducing coolant gas in the shaft furnaces
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21B—MANUFACTURE OF IRON OR STEEL
    • C21B2100/00—Handling of exhaust gases produced during the manufacture of iron or steel
    • C21B2100/20—Increasing the gas reduction potential of recycled exhaust gases
    • C21B2100/22—Increasing the gas reduction potential of recycled exhaust gases by reforming
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P10/00—Technologies related to metal processing
    • Y02P10/10—Reduction of greenhouse gas [GHG] emissions
    • Y02P10/134—Reduction of greenhouse gas [GHG] emissions by avoiding CO2, e.g. using hydrogen
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P10/00—Technologies related to metal processing
    • Y02P10/10—Reduction of greenhouse gas [GHG] emissions
    • Y02P10/143—Reduction of greenhouse gas [GHG] emissions of methane [CH4]

Definitions

  • This application relates to the reforming of the hydrocarbons pentane and higher into the reductants carbon monoxide and hydrogen for use as reducing gas.
  • gases are commonly utilized for the direct reduction of metal oxides to the metallized form by the use of reducing gases.
  • the present invention is particularly well suited to the direct reduction of iron from particulate iron or oxides.
  • processes such as the direct reduction of iron utilize gases, such as natural gas, which consists principally of methane (CH 4 ), with some ethane (C 2 H 6 ), propane (C 3 H 8 ), and butane (C 4 H 10 ). Natural gas also contains some higher hydrocarbons, pentane (C 5 H 12 ), hexane (C 7 H 16 ), heptane (C 6 H 18 ), etc.
  • the present invention is a method for the direct reduction of metal oxides in a shaft furnace direct reduction process utilizing gases containing higher hydrocarbons.
  • natural gas containing higher hydrocarbons is passed through a portion of the hot burden in a direct reduction shaft furnace, after which the gas is removed and reformed.
  • the higher hydrocarbons are cracked and partially reformed within the furnace because of the large surface area of the burden which acts as a catalyst.
  • the cracking of the higher hydrocarbons causes their partial reformation to carbon monoxide and hydrogen along with deposition of carbon on the material in the burden. This is advantageous because additional carbon is frequently desired in the end product.
  • the main advantage is to cause any carbon deposition to occur within the reduction furnace and not in the reformer.
  • FIG. 1 is a schematic drawing of a shaft furnace direct reduction process flow sheet utilizing the invented process, and which results in a hot product discharge.
  • FIG. 2 is a flow sheet similar to FIG. 1 showing an alternative embodiment utilizing the invented process, and which results in cold product discharge.
  • shaft furnace 10 is provided with feed means, shown as feed pipes 12, at the top thereof, and a product withdrawal or discharge pipe 14 at the bottom thereof.
  • feed means shown as feed pipes 12, at the top thereof, and a product withdrawal or discharge pipe 14 at the bottom thereof.
  • Particulate oxides such as iron oxide in the form of lumps or pellets, are fed through pipes 12 to form a packed bed burden 16 within the shaft furnace.
  • the speed of descent of the burden is controlled by the removal of treated burden material from the bottom of the furnace.
  • a hot bustle gas inlet 20 which introduces hot reducing gas to the furnace through a plurality of gas inlet ports arranged in the furnace wall.
  • a second gas inlet 24 which communicates with a source 26 of process gas and/or natural gas containing higher hydrocarbons via pipe 28 having a control valve 29 therein.
  • Preferably four such pipes 28 are utilized, one feeding each quadrant of the bustle.
  • Gas inlet ports 24 are arranged completely around the perimeter of the furnace wall in a manner such that each pipe 28 is connected to a 90° sector of gas inlet ports 24. Valves 29 are operated to introduce gas to one or more of the 90° sectors of gas inlet ports 24 in a sequential manner.
  • a hot gas off-take 30 is located at the top of the shaft furnace.
  • a gas pipe 32 communicates between off-take 30 and cooler-scrubber 34, which is provided with a gas withdrawal pipe 36.
  • a second, lower, gas off-take 38 between the top of the burden stockline 40 and the elevation of upper off-take 30 is connected to pipe 42 which communicates with scrubber 44.
  • Gas from scrubber 44 passes through pipe 46, compressor 48 and pipe 50, then is introduced to reformer 54 containing a plurality of heat resistant alloy reformer tubes 56, only one of which is shown.
  • Each tube 56 is filled with ceramic reforming catalyst such as alumina, at least a portion of which is generally nickel impregnated.
  • the tubes are enclosed within refractory lined reformer furnace 54 having heating burners 60, only one of which is shown, which heat the tubes and the reforming catalyst therein.
  • a reformed gas pipe 64 connects the reformed gas outlet of reformer 54 to bustle gas inlet 20 to complete the gas circuit.
  • Top gas fuel can be withdrawn from the system through line 67. This is preferably utilized as the primary fuel to heat the reformer.
  • FIG. 1 results in hot discharge of particulate metallized particles through discharge pipe 14.
  • process gas and/or natural gas containing higher hydrocarbons from source 26 are fed through line 28 to bustle gas inlet 24.
  • the gas mixture containing higher hydrocarbons tends to flow along the wall of the furnace, as the reformed gases introduced through lower inlets 20 move more through the center of the burden as they pass upwardly in counter-flow relation to the downwardly descending burden.
  • Valves 29 are operated sequentially. When a valve 29 is closed, the upper portion of the burden is preheated by the rising hot reducing gas in that 90° sector of the furnace.
  • the gas mixture containing the higher hydrocarbons passes through the previously preheated burden and the higher hydrocarbons crack, commencing to reform thermally into hydrogen and carbon monoxide, forming some H 2 O, carbon dioxide and free carbon, the latter being deposited on the particles in the burden.
  • the partially reformed gases are withdrawn through lower top-gas off-take 38 and pipe 42, then cooled and scrubbed in scrubber 44 and delivered to reformer 54 through pipe 50.
  • the hot spent higher hydrocarbon lean top-gas is removed through off-take 30 and passed through pipe 32 into cooler-scrubber 34, after which it is removed by line 36 and mixed with the cooled, scrubbed, partially reformed process gas from line 46. Due to expansion in the system, a certain amount of top gas fuel will be formed, which is removed through line 67 and delivered to the reformer burners 60. Additional natural gas fuel can be introduced to line 67 from natural gas source 70, as required.
  • the alternative embodiment shown in FIG. 2 utilizes a cooling gas system to cool the metallized product within the shaft furnace 110 prior to discharge through pipe 114.
  • the process gas and/or natural gas from source 126 is introduced to the shaft furnace to a point beneath the bustle gas inlet 120.
  • the hot burden partially reforms and cracks the higher hydrocarbons, after which these gases are removed from the furnace along with the spent cooling gas.
  • shaft furnace 110 has a bustle gas inlet 120 for introduction of hot reducing gas.
  • Hot spent top gas is removed from the top of the furnace through spent off take 130 located between the burden stock line 140 and the top of the furnace.
  • a pipe 132 communicates with a cooler-scrubber 134.
  • Cleaned cooled gas from the scrubber passes through compressor 148 and pipe 150, then is introduced to the cooling zone of the shaft furnace via a cooling gas distributor 152.
  • Gas collectors 154 above the cooling gas distributor remove the partially reformed gases and the spent cooling gases from the furnace. This gas mixture is passed through cooling gas off-take 158, cooler 160, compressor 161 and then is passed into stoichiometric reformer 162.
  • Process gas of natural gas is introduced to the furnace 110 through bustle gas inlets 170.
  • process gas is heated by the hot descending burden and is drawn downwardly by the cooling gas collectors 154, where it mixes with the hot cooling gas, then the mixture is removed from the system through off-take 158, is cleaned, and cooled in scrubber-cooler 160, and delivered to the reformer 162.
  • the process gas containing higher hydrocarbons is reformed along with spent cooling gas.
  • the process gas is partially reformed and cracked by the hot burden material within the shaft furnace prior to introducing the process gas containing higher hydrocarbons to the stoichiometric reformer.

Landscapes

  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Manufacturing & Machinery (AREA)
  • Materials Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Manufacture Of Iron (AREA)
  • Hydrogen, Water And Hydrids (AREA)
  • Industrial Gases (AREA)
  • Manufacture Of Metal Powder And Suspensions Thereof (AREA)
  • Manufacture And Refinement Of Metals (AREA)
US06/648,564 1984-09-10 1984-09-10 Reforming of higher hydrocarbons for metal oxide reduction Expired - Lifetime US4536213A (en)

Priority Applications (14)

Application Number Priority Date Filing Date Title
US06/648,564 US4536213A (en) 1984-09-10 1984-09-10 Reforming of higher hydrocarbons for metal oxide reduction
CA000483992A CA1236982A (en) 1984-09-10 1985-06-14 Reforming of higher hydrocarbons
AU45302/85A AU4530285A (en) 1984-09-10 1985-07-24 Direct reduction of iron oxide and reforming natural gas
AT0234085A AT390081B (de) 1984-09-10 1985-08-09 Verfahren zum reduzieren von metalloxid zu metallisiertem material unter verwendung von pentan und hoeheren kohlenwasserstoffen
ZA856109A ZA856109B (en) 1984-09-10 1985-08-13 Reforming of higher hydrocarbons
DE19853529226 DE3529226A1 (de) 1984-09-10 1985-08-14 Verfahren zum reformieren von hoeheren kohlenwasserstoffen und zur reduktion von metalloxiden
IN595/CAL/85A IN164016B (it) 1984-09-10 1985-08-16
GB08520684A GB2164355B (en) 1984-09-10 1985-08-19 Process for reducing metallic oxide to metallized material
CN 85106482 CN85106482A (zh) 1984-09-10 1985-08-20 高级烃类的重整
BR8504028A BR8504028A (pt) 1984-09-10 1985-08-22 Reforma de hidrocarbonetos superiores
FR8512706A FR2570082A1 (fr) 1984-09-10 1985-08-26 Procede de reduction d'oxyde metallique a l'aide de gaz reducteurs provenant du reformage du pentane ou d'hydrocarbures superieurs
IT22044/85A IT1187734B (it) 1984-09-10 1985-09-02 Reforming degli idrocarburi superiori
SE8504177A SE8504177L (sv) 1984-09-10 1985-09-09 Reformering av hogre kolveten
JP60198694A JPS6173805A (ja) 1984-09-10 1985-09-10 金属酸化物の還元方法

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US06/648,564 US4536213A (en) 1984-09-10 1984-09-10 Reforming of higher hydrocarbons for metal oxide reduction

Publications (1)

Publication Number Publication Date
US4536213A true US4536213A (en) 1985-08-20

Family

ID=24601314

Family Applications (1)

Application Number Title Priority Date Filing Date
US06/648,564 Expired - Lifetime US4536213A (en) 1984-09-10 1984-09-10 Reforming of higher hydrocarbons for metal oxide reduction

Country Status (13)

Country Link
US (1) US4536213A (it)
JP (1) JPS6173805A (it)
AT (1) AT390081B (it)
AU (1) AU4530285A (it)
BR (1) BR8504028A (it)
CA (1) CA1236982A (it)
DE (1) DE3529226A1 (it)
FR (1) FR2570082A1 (it)
GB (1) GB2164355B (it)
IN (1) IN164016B (it)
IT (1) IT1187734B (it)
SE (1) SE8504177L (it)
ZA (1) ZA856109B (it)

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4720299A (en) * 1985-05-13 1988-01-19 Voest-Alpine Aktiengesellschaft Method for the direct reduction of particulate iron-oxide-containing material
US4756750A (en) * 1987-04-27 1988-07-12 Air Products And Chemicals, Inc. Process for the direct reduction of iron ore
GB2265152A (en) * 1992-03-05 1993-09-22 Orinoco Siderurgica A method for improving quality of reforming gas used in the direct reduction of metal oxides
WO2000036156A1 (en) * 1998-12-11 2000-06-22 Danieli & C. Officine Meccaniche Spa Method and apparatus for the direct reduction of iron oxides
DE102006062689A1 (de) * 2006-12-21 2008-06-26 Mines And Metals Engineering Gmbh (M.M.E.) Verfahren für die direkte Reduktion von Eisenoxid
EP1930678A3 (en) * 2006-12-11 2008-12-31 Mines and Metals Engineering (M.M.E.) Shaft furnace
EP3535424A4 (en) * 2016-11-03 2020-04-29 Midrex Technologies, Inc. DIRECT REDUCTION METHOD AND TANK OVEN USING EXTENDED FLOW DIVERTER CONE

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3392008A (en) * 1965-07-29 1968-07-09 Exxon Research Engineering Co Production of iron
US4032120A (en) * 1975-11-10 1977-06-28 Midrex Corporation Apparatus for direct reduction of sulfur-containing iron ore
US4054444A (en) * 1975-09-22 1977-10-18 Midrex Corporation Method for controlling the carbon content of directly reduced iron

Family Cites Families (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1310050A (en) * 1970-11-11 1973-03-14 Tsnii Chernoimetallurgii Im I Carbonized iron production
JPS5847449B2 (ja) * 1978-04-10 1983-10-22 株式会社神戸製鋼所 直接製鉄法
US4216011A (en) * 1979-04-23 1980-08-05 Hylsa, S.A. Method and apparatus for the secondary gaseous reduction of metal ores
US4261734A (en) * 1979-09-04 1981-04-14 Hylsa, S.A. Method of making sponge iron
US4270739A (en) * 1979-10-22 1981-06-02 Midrex Corporation Apparatus for direct reduction of iron using high sulfur gas
US4246024A (en) * 1979-10-31 1981-01-20 Grupo Industrial Alfa, S.A. Method for the gaseous reduction of metal ores using reducing gas produced by gasification of solid or liquid fossil fuels
US4351513A (en) * 1981-01-29 1982-09-28 Midrex Corporation Direct reduction of iron using coke oven gas
JPS5871314A (ja) * 1981-10-21 1983-04-28 Kobe Steel Ltd 還元鉄の連続製造法およびそれに用いる装置
DE3244744A1 (de) * 1982-11-25 1984-05-30 Klöckner-Werke AG, 4100 Duisburg Verfahren zur direktreduktion von eisenerz im schachtofen

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3392008A (en) * 1965-07-29 1968-07-09 Exxon Research Engineering Co Production of iron
US4054444A (en) * 1975-09-22 1977-10-18 Midrex Corporation Method for controlling the carbon content of directly reduced iron
US4032120A (en) * 1975-11-10 1977-06-28 Midrex Corporation Apparatus for direct reduction of sulfur-containing iron ore

Cited By (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4720299A (en) * 1985-05-13 1988-01-19 Voest-Alpine Aktiengesellschaft Method for the direct reduction of particulate iron-oxide-containing material
US4756750A (en) * 1987-04-27 1988-07-12 Air Products And Chemicals, Inc. Process for the direct reduction of iron ore
GB2265152A (en) * 1992-03-05 1993-09-22 Orinoco Siderurgica A method for improving quality of reforming gas used in the direct reduction of metal oxides
GB2265152B (en) * 1992-03-05 1995-12-20 Orinoco Siderurgica A method for improving quality of reforming gas used in the direct reduction of metal oxides
WO2000036156A1 (en) * 1998-12-11 2000-06-22 Danieli & C. Officine Meccaniche Spa Method and apparatus for the direct reduction of iron oxides
US6319301B1 (en) 1998-12-11 2001-11-20 Danieli & C. Officine Meccaniche Spa Method for the direct reduction of iron oxides
US6551549B2 (en) 1998-12-11 2003-04-22 Danieli & C. Officine Meccaniche Spa Apparatus for the direct reduction of iron oxides
EP1930678A3 (en) * 2006-12-11 2008-12-31 Mines and Metals Engineering (M.M.E.) Shaft furnace
DE102006062689A1 (de) * 2006-12-21 2008-06-26 Mines And Metals Engineering Gmbh (M.M.E.) Verfahren für die direkte Reduktion von Eisenoxid
DE102006062689B4 (de) * 2006-12-21 2009-01-22 Mines And Metals Engineering Gmbh (M.M.E.) Schachtofen für die direkte Reduktion von Eisenoxid
EP3535424A4 (en) * 2016-11-03 2020-04-29 Midrex Technologies, Inc. DIRECT REDUCTION METHOD AND TANK OVEN USING EXTENDED FLOW DIVERTER CONE

Also Published As

Publication number Publication date
SE8504177D0 (sv) 1985-09-09
FR2570082A1 (fr) 1986-03-14
ATA234085A (de) 1989-08-15
ZA856109B (en) 1986-03-26
IT8522044A0 (it) 1985-09-02
CA1236982A (en) 1988-05-24
IN164016B (it) 1988-12-31
JPS6173805A (ja) 1986-04-16
BR8504028A (pt) 1986-06-10
GB2164355B (en) 1988-11-16
AU4530285A (en) 1986-03-20
SE8504177L (sv) 1986-03-11
IT1187734B (it) 1987-12-23
DE3529226A1 (de) 1986-03-20
AT390081B (de) 1990-03-12
GB8520684D0 (en) 1985-09-25
GB2164355A (en) 1986-03-19

Similar Documents

Publication Publication Date Title
US4054444A (en) Method for controlling the carbon content of directly reduced iron
US4046557A (en) Method for producing metallic iron particles
EP0033128B1 (en) Catalytic steam reforming of hydrocarbons
US4824658A (en) Production of synthesis gas using convective reforming
US4270739A (en) Apparatus for direct reduction of iron using high sulfur gas
EP0440258B1 (en) Heat exchange reforming process and reactor system
US5006131A (en) Apparatus for production of synthesis gas using convective reforming
US3749386A (en) Method and means for reducing iron oxides in a gaseous reduction process
KR850001644B1 (ko) 코우크스로게스를 이용한 철의 직접 환원 장치
GB2239261A (en) A process for the direct reduction of metal oxides
US4087275A (en) Method for direct reduction of sulfur-containing iron ore
SU995708A3 (ru) Способ восстановлени дисперсной железной руды до губчатого железа
CN107881280A (zh) 一种还原并冷却金属化球团的系统及方法
JPS5810965B2 (ja) 粒状鉄鉱石のスポンジ鉄粒子への還元方法
US4536213A (en) Reforming of higher hydrocarbons for metal oxide reduction
GB2188066A (en) Increasing carbon content of hot directly reduced iron
CA1228482A (en) Reduction of metal compounds
US2990269A (en) Refining of ores with hydrocarbon gases
US4416689A (en) Process for the manufacture of crude iron and energy-rich gases
CA1075913A (en) Method and apparatus for producing metallic iron particles
US4439233A (en) Direct reduction of iron
US4333761A (en) Method for direct reduction of iron using high sulfur gas
NO137647B (no) Fremgangsm}te og apparatur for direkte reduksjon av jernmalm
US4049440A (en) Method for producing metallic iron pellets
US3964898A (en) Process for batch production of sponge iron

Legal Events

Date Code Title Description
AS Assignment

Owner name: MIDREX INTERNATIONAL BV A CORP. OF THE NETHERLAND

Free format text: ASSIGNMENT OF ASSIGNORS INTEREST.;ASSIGNOR:SANZENBACHER, CHARLES W.;REEL/FRAME:004308/0931

Effective date: 19840829

STCF Information on status: patent grant

Free format text: PATENTED CASE

FEPP Fee payment procedure

Free format text: PAYOR NUMBER ASSIGNED (ORIGINAL EVENT CODE: ASPN); ENTITY STATUS OF PATENT OWNER: LARGE ENTITY

FPAY Fee payment

Year of fee payment: 4

FPAY Fee payment

Year of fee payment: 8

REFU Refund

Free format text: REFUND OF EXCESS PAYMENTS PROCESSED (ORIGINAL EVENT CODE: R169); ENTITY STATUS OF PATENT OWNER: LARGE ENTITY

FPAY Fee payment

Year of fee payment: 12

AS Assignment

Owner name: NATIONSBANK, N.A., AS AGENT, NORTH CAROLINA

Free format text: SECURITY INTEREST;ASSIGNOR:AMERICAN IRON REDUCTION, L.L.C.;REEL/FRAME:008401/0703

Effective date: 19960830